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    <title>Document</title>
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<script>
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    // let arr1=arr
    // arr1[0]="12345"
    // console.log(arr1)


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        a:undefined,
        b:{
            c: function() {
                console.log(1)
            },
            d: null,
            e: new Date(),
            f: new RegExp('\\w+'),
            g: NaN
        },
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    let copyObj = JSON.parse(JSON.stringify(obj))
    console.log(obj, copyObj)

</script>
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